Substituted 6-nitroaniline compounds and herbicidal compositions

ABSTRACT

Novel 6-nitroaniline compounds of the formula   IN WHICH R1 is hydrogen, substituted or unsubstituted alkyl or aryl, or cycloalkyl; R2 is hydrogen, alkyl or alkenyl; and R1 and R2 together can form a heterocycle; AND OF X and Y one is cyano and the other trifluoromethyl ARE HERBICIDES HAVING OUTSTANDING ACTIVITY AND SELECTIVITY.

United States Patent 1191 Wagner et al.

[ Nov. 18, 1975 SUBSTITUTED 6-NITROANILINE COMPOUNDS AND HERBICIDAL COMPOSITIONS [75] Inventors: Klaus Wagner; Ludwig Eue, both of Cologne; Erich Klauke, Odenthal,

all of Germany [73] Assignee: Bayer Aktiengesellschait,

, Leverkusen, Germany [22] Filed: July 6, 1973 21 App]. No.: 376,991

' --Related us. Application Data [62] Division of Ser. NO. 114,071, Feb. 9, 1971, Pat. No.

[30] Foreign Application Priority Data 3,257,190 6/1966 Sopen 71/105 Primary Examiner-James 0. Thomas, Jr. Attorney, Agent, or Firm-Burgess, Dinklage & Sprung 7] ABSTRACT Novel 6-nitroaniline compounds of the formula in which R is hydrogen, substituted or unsubstituted alkyl or v aryl, or cycloalkyl;

R is hydrogen, alkyl or alkenyl; and

R and R together can form a heterocycle;

and 'of X and Y one is cyano and the other trifluoromethyl are herbicides having outstanding activity and selectivity. Y

8 Claims, No Drawings 1 SUBSTITUTED 6-NITROANILINE COMPOUNDS AND HERBICIDAL COMPOSITIONS This is a division, of application Ser. No. 114,071

filed Feb. 9, 1971, now U.S. Pat. No. 3,781,323.

0 M Y (I) in which R, is hydrogen, alkyl, hydroxyalkyl, alkoxyalkyl, alkenyl, cycloalkyl, e.g. with from 4 to 6 ring carbons; aralkyl or unsubstituted or substituted aryl, e.g. phenyl or naphthyl;

R is hydrogen, alkyl or alkenyl or R, and R together with the nitrogen atom to which they are attached, form-a heterocyclic radical with from, e.g., 4 to 5 ring carbons;

K X and Y are selected from the group consisting of tri- 'fluoromethyl and cyano with-the proviso that one of X and Y is trifluoromethyl and the other cyano. Preferably, when R, and R are or contain alkyl or alkenylradicals, such radicals are lower alkyl or alltenyl of, e.g., up scheme:

OCH

. 3 Cl 0 N pyridinD/POC] o c H (1) 1 cr a 7 3 7 3 cu (N c H x 3 7 N o u x 2 H ln) on y N NH -c H (n) r" C cu on v v g a to 8 carbon atoms. Generally, the total number of carbon atoms in R, and R will not exceed about 10.

Such compounds have been found to exhibit strong herbicidal properties.

The invention also provides a process for the production of a substituted 6-nitroaniline derivative of the formula (l) in which a l-alkoxy-6-nitrobenzene derivative of the general formula 3 0 st) Y (11) in which X and Y are defined as above, and R is alkyl, is either a. reacted with a compound of the formula in which R, and R are defined as above, optionally in the presence of a solvent,

or I

b. converted by reaction with pyridine and phosphorus oxychloride, optionally in the presence of a solvent, into the appropriate l-chloro-6-nitrobenzene derivative and this is reacted with a compound of the above formula (III), optionally in the presence of an acidbinding agent.

If 1-methoxy-2-cyano-4-trifluoromethyl-6-nitrobenzene and n-butylamine are used as starting materials, the reaction. course according to process variant (a) can be represented by the following formula scheme:

, If l-methoxy-Z-triflu o'romethyl-4-cyano-6-nitrobenzene and di-n-propylamine are used according to process variant (b) as starting materials, the reaction 50 course can be represented by the following formula CN (V) The l-alkoxy--nitrobenzene derivatives used as starting materials are unambiguously characterized by the formula (11).

R is preferably alkyl with 1 to 4 carbon atoms.

As examples of compounds of formula II, there are mentioned: l-methoxy-2-cyano-4-trifluor0methyl-6- nitrobenzene and l-ethoxy-2-trifluoromethyl-4-cyano- 6-nitrobenzene.

The l-alkoxy-6-nitrobenzene derivatives of the formula II are not yet known, but can be readily prepared by first reacting l-ch1oro-2-cyano-4-trifluoromethy1- benzene (cf. Helv. Chim. Acta 45, 2226-2241 (1962)) or l-chloro-2-trifluoromethyl-4-cyano-benzene (cf. Compt. Rend. 257 (21), 3182-3184 (1963)) with alkoxides in the presence of polar solvents, preferably a1- cohols such as methanol or ethanol, at temperatures of about 50l00C, to give the appropriate l-alkoxybenzenes, and subsequently nitrating these with nitric acid at a temperature of to C.

The following Examples are intended to illustrate this preliminary process:

EXAMPLE A Preparation of 2-cyano-4-trifluoromethyl-anisolez To a sodium methylate solution prepared from 23 g (l gram-atom) of sodium and 1000 ml of mathanol there were added, in portions,'205 g (1 mole) l-chloro- 2-cyano-4-trifluoromethylbenzene at 60 65C, and boiled under reflux'was effected for 8 hours. After cooling, the separated sodium chloride'was filtered off with suction and the excess methanol was distilled off in a vacuum. The oil remaining behind was taken up in methylene chloride, and the solution was washed with water and dried over sodium sulfate. After the methylene chloride had been distilled off in a vacuum, 166 g (82% of the theory) of 2-cyano-4-trifluoromethylanisole of the boiling point 90C at 0.12 mml-lg were obtained. After standing for a longer period, the product crystallized in the form of pale-yellow needles of melting point 33 34C.

EXAMPLE B Preparation of 300 ml of nitric acid ((1 1.52) were cooled to 5C, and 60 g 2-cyano-4-trifluoromethylanisole were added, in portions, with vigorous stirring; the temperature did not exceed 10C. The reaction mixture was kept at 0 5C for a further 2 hours, pouring on to ice was effected, the nitration product was taken up in methylene chloride, the organic phase was washed neutral with water, and the methylene chloride solution was dried over sodium sulfate. After the solvent had been drawn off in a vacuum, 52 g (7 1% of the theory) of 2-cyano-4- trifluoromethyl-6-nitro-anisole were obtained in the form of a reddish-yellow oil which solidified into yellow crystals in an ice box.

In corresponding manner, starting from l-chloro-2- trifluoromethyl-4-cyanobenzene, there is prepared 2- trifluoro-methyl-4-cyano-6-nitroanisole.

The compounds of the formula III used as starting materials are known.

Most preferably, R is hydrogen, alkyl with l to 4 carbon atoms, hydroxyalkyl with l to 4 carbon atoms, alkoxyalkyl with l to 4 carbon atoms in each of the alkyl and alkoxy moieties, alkenyl with 2 to 4 carbon atoms, cycloalkyl with 5 to 6 carbon atoms, aralkyl with 1 to 2 carbon atoms in the alkyl moiety, or phenyl (which phenyl may be substituted by chlorine, bromine, trifluromethyl and/or methyl), and R is hydrogen alkyl with 1 to 4 carbon atoms or alkenyl with 2 to 4 carbon atoms; or R and R together with the nitrogen atom and optionally also oxygen or sulfur atoms, form a 5- to 6-membered ring.

As examples of compounds of formula (111), there can be mentioned: ammonia, methylamine, ethylamine, n-propylamine, 2-hydroxyethylamine, 2- methoxyethylamine, iso-butylamine, tert.-buty1amine, allylamine, cyclohexylamine, benzylamine, dimethylamine, diethylamine, di-n-propylamine, di-n-butylamine, diallylamine, aniline, pyrrolidine, piperidine and morpholine.

Preferred solvents for the reaction of process variant (a), include alcohols, such as methanol or ethanol, and ketones, such as acetone or methylethyl ketone. For the reaction of process variant (b), invert organic solvents are mainly suitable; these include hydrocarbons, such as benzene or toluene; ethers, such as diethyl ether, tetrahydrofuran or dioxan; esters, such as ethyl acetate; and nitriles, such as acetonitrile.

As acid-binders, all customary acid-binding agents can be used. Preferred examples include alkali metal hydroxides, alkali metal carbonates and tertiary amines. Especially suitable are triethylamine and pyridine, and preferably an excess of the compound of for mula Ill.

The reaction temperatures can be varied within a fairly wide range. In general, reaction (a) is carried out at 20 to C, preferably 40 to 80C; reaction (b) at 40 to 160C, preferably 60 to C.

When carrying out process variant (a), it is preferred to use approximately stoichiometric proportions. ln process variant (b), the components are, in general, likewise used in equiinolar amounts. If excess of the amine of formula III is used as acid-binding agent, preferably 2.2 2.5 moles of this amine are used for each mole of the compound of formula 11.

The working up of the reaction mixtures maybe effected in customary manner. a

The active compounds of this invention exhibit a strong herbicidal, particularly selective, potency. They can therefore be used for the control of weeds. As weeds in the widest'sense are meant all plants which grow in places where they are not desired. Whether the substances according to the invention act as total or as selective herbicides depends essentially on the amount applied.

The substances according to the invention can be used for example in the case of the following plants: dicotyledons, such as mustard (Sinapis), cress (Lepidium), cleaver (Galium), common chickweed (Stellaria), mayweed (Matricaria), smallflower Galinsoga (Galinsoga), fathen (Chenopodium), stinging nettles (Urtica), grounsel (Senecio), cotton (Gossypium), beets (Beta), carrots (Daucus), beans (Phaseolus), potatoes (Solarium), coffee (Coffea); monocotyledons, such as timothy (Phleum), bluegrass (Poa), fescue (Festuca), goosegrass (Eleusine), foxtail (Setaria), ryegrass (Lolium), cheat (Bromus), barnyard grass (Echinochloa), corn (Zea), rice (Oryza), oats ,(Avena), barley (Hordeum), wheat (Triticum), millet (Panicum), sugar cane (Saccharum).

Particularly advantageous is the use for weed control in cereals, maize and cotton.

The active compounds according to the present invention can be converted into the usual formulations, such as solutions, emulsions, suspensions, powders, pastes and granulates. These may be produced in known manner, for example by mixing the active compounds with extenders, that is, liquid or solid diluents of carriers, optionally with the use of surface-active agents, that is, emulsifying agents and/0r dispersing agents. In the case of the use of water as an extender organic solvents can, for example, also be used as auxiliary solvents. I

As liquid diluents or carriers, there are preferably used aromatic hydrocarbons, such as xylenes or ben-' zene, chlorinated aromatic hydrocarbons, such as chlorobenzenes, paraffins, such as mineral oil fractions, al-

cohols, such as methanol or butanol, or strongly polar solvents, such as dimethyl formamide or dimethyl sulfoxide, as well as water. 1 As solid diluents or carriers, thre are preferably used ground natural minerals, such as kaoline, clays, tale or 6 chalk, or ground synthetic minerals, such as highly-dispersed silicic acid or silicates.

Preferred examples of emulsifying agents include nonionic and anionic emulsifiers, such as polyoxyethylene-fatty acid esters, polyoxyethylene-fatty alcohol ethers, for example alkylarylpolyglycol ethers, alkyl sulphonates and aryl'sulphonates; and preferred examples of dispersingagents include lignin, sulfite waste liquors and methyl cellulose.

The active compounds according to the invention may be present in the formulations in admixture with other active compounds or may be mixed at the time of application.

The formulations contain, in general, 0.1 to 95, preferably 0.5 to 90, percent by weight of active compound.

The active compounds may be applied as such or in the form of their formulations or of the application forms prepared therefrom, such as ready-to-use solutions, emulsions, suspensions, poweders, pastes and granulates. Application may .take place in the usual manner, for example by spraying, squirting, dusting or scattering.

,When the compounds are applied as total herbicides, the amounts of active compounds are usually 40 kg/hectare. In the case of use for selective weed control, the amounts applied are usually 1 20 kg/hectare, preferably 2 l0 kg/hectare.

The active compounds can be used both before and after the emergence of the cultivated plants and weeds, chiefly before the emergence.

The active compounds according to the invention also exhibit insecticidal and fungicidal properties.

The invention therefore procides a herbicidal composition containing as active ingredient a compound according to the invention in admixture with a solid diluent or carrier or in admixture with a liquid diluent or carrier containing a surface-active agent.

The invention also provides a method of combating weeds which comprises applying to the weeds or a weed habitata compound according to the invention alone or in the form of a composition containing as acfive-ingredient acompound according to the invention in admixture with a solid or liquid diluent or carrier.

The invention is illustrated by the following Examples, in which the following were used as test compounds illustrative of the present invention:

EXAMPLE A Pre-emergence test Solvent: parts by weight acetone Emulsifier: 1 part by weight alkylaryl polyglycol ether To produce a suitable preparation of active compound, 1 part by weight of active compound is mixed with the stated amount of solvent, the stated amount of emulsifier is added and the concentrate is then diluted with water to the desired concentration.

A rapid, continuous stream of Nl l was introduced for 10 minutes into a solution (which has a temperature of 60C) of 12.3 g (0.05 mole) 2-cyano-4-trifluoromethyl--nitroanisole (Formula B) in 100 ml methanol, and the reaction mixture was subsequently stirred at 60C for 1 hour. Water was then added to the reaction mixture until it became turbid. During cooling, 11 g (95% of the theory) of 2-cyano-4-trifluoromethyl--nitroaniline crystallized in orange-yel- 10 low needles of the melting point 118 119C. Seeds of the test plants are sown in normal soil and, after 24 hours, watered with the preparation of the ac- EXAMPLE 2 tive compound. It is expedient to keep constant the Preparation of amount of water per unit area. The concentration of 2-cyano-4-trifluoromethyl-6-nitro-N-methylaniline the active compound in the preparation is of no impor- 15 tance, only the amount of active compound applied per unit area being decisive. After three weeks, the degree Nil-CH of damage to the test plants is determined and characterized by the values 0 5, which have the following I meaning:

0=no effect l=slight damage or delay in growth v CF, 2=marked damage or inhibition of growth 3=heavy damage and only deficient development or only 50% emerged a 4=plants partially destroyed after germination or 12.3 g (0.05 mole) 2-cyano-4-tritluoromethyl-6- only 25% emerged nitroanisole (Formula B) were dissolved in 100 ml 5=plants completely dead or not emerged. methanol. To this solution there were added slowly, at The active compounds, the amounts applied and the C, with stirring, 7 ml of a 40%-strength aqueresults obtained can be seen from Table A. 30 ous methylamine solution, and the reaction mixture Table A Pre-emergence test Active compound Active Echi- Cheno- Stella- Lolium Oats Barley Rye Rice Wheat compound nopodium ria applied chloa kg/hectare C H,- 0,N N/ a n 10 2 0 0 0 0 0 0 0 0 cn-n-n 5 0 0 0 0 0 0 0 0 0 CN (known) 10 4-5 4 4 5 2 '0 0 1 0 Compound 1 5 4 3 3 4-5 1 0 0 0 0 Compound 2 10 5 5 5 5 5 5 5 5 5 5 5 4 5 5 5 4 4-5 4-5 5 Compound 3 l0 '5 5 5 5 l 1 0 2 o 5 4-5 4 4 4-5 0 0 0 EXAMPLE 1 was afterwards stirred for a further 30 minutes at 60C.

During cooling, 9 g, (73% of the theory) of 2-cyano-4- trifluoromethyl-6-nitro-N-methylaniline crystallized in orange-yellow needles of the melting point 101 102C.

EXAMPLES 3 9 1n corresponding manner, the compounds set forth in Table B, below, were prepared in Table B and with reference to formula 1, above, X is C1 Y is CN and R, and R are as set forth in the Table.

Table B Example No. R R Melting point (C) 5 H CH CH -OCH 76 77 e H cH,-cH, cH, 60 61 7 H CH(CH 100 l] 8 H CH CH -CH -CH 66 67 9 H CH CH(CH 88 89 EXAMPLE 10 Preparation of 2-cyano-4-trifluoromethyl-6-nitro-N,N-di-n-propylaniline ON C H --n r 7 F 0 C H n 24.6 (0.1 mole) 2-cyano-4-trifluoromethyl-6- nitroanisole (Formula B) in 250 ml xylene with 8 g(O.l

mole) pyridine were heated to 120 130C, for 10 minutes. The reaction mixture was cooled to 90C and 5.5 ml (0.06 mole) phosphorus oxychloride were added dropwise, and stirring was afterwards effected for 1 hour at 110C. After cooling of the reaction mixture to 80C, 23.8 g (0.23 mole) -di-n-propylamine were added dropwise, with stirring, and the reaction -mixture was stirred for a further 30 minutes at 90C.

After cooling, the separated di-n-propylamine hydrochloride was filtered off with suction, the organic phase was washed several timeswith water, drying over sodium sulfate was effected, and the xylene was distilled offin a vacuume. The oily residue crystallized throughcompletely in an ice box. After suction filtration and washing with a little cold petroleum ether, l0 g (32% of general formula in which R is hydrogen, alkyl of from 1 to 4 carbon atoms, hydroxyalkyl of from 1 to 4 carbon atoms, or alkoxyalkyl of from 1 to 4 carbon atoms in each of the alkyl or alkoxy moieties, alkenyl of from 2 to 4 carbon atoms, cycloalkyl of from 5 to 6 carbon atoms, aralkyl of from 1 to 2 carbon atoms or unsubstituted or substituted phenyl;

R is hydrogen or alkyl or alkenyl of up to 4 carbon atoms; and

X and Y are selected from the group consisting of trifluoromethyl and cyano with the proviso that one of X and Y is tritluoromethyl and the other cyano.

2. Methods of combating undesired vegetation which comprises applying an effective amount of a 6- nitroanile compound of the formula to 2 carbon atoms or unsubstituted or substituted 3. Method as claimed in claim 2 wherein said com- 5 pound is. applied to weeds growing in a crop to selectively damage the weeds without substantial injury to the crop.

4. Method as claimed in claim 2 wherein R is hydrogen or alkyl of from 1 to 4 carbon atoms, and R is hydrogen, alkyl of from 1 to 4 carbon atoms or alkenyl of from 2 to 4 carbon atoms.

5. Method as claimed in claim 2 wherein said compound is selected from the group consisting of 2-cyano- 4-trifluoromethyl-6-nitro-N-n-butylaniline, 2-cyano-4- trifluoromethyl-6-nitro-N,Ndi-n-propylaniline, 2- cyano-4-trifluoromethyl-6-nitro-N-n-propylaniline, 2- cyano-4-trifluoromethyl-6-nitroaniline, 2-cyano-4-trifluoromethyl-6-nitro-N-methylaniline, 2-cyano-4-trifluoromethyl-6-nitro-N-ethylaniline, 2-cyano-4-trifluoromethyl-6-nitro-N-2-hydroxyethylaniline, 2- cyano-4-trifluoromethyl-6nitro-N-2-methoxyethylaniline, 2-cyano-4-trifluoromethyl-6-nitro-N-isopropylaniline 2-cyano-4-trifluoromethyl-6-nitro-N-isobutylaniline.

6. Method as claimed in claim 2 wherein said compound is 2-cyano-4-trifluoromethyl-6-nitro-N-nbutylaniline.

7. Method as claimed in claim 2 wherein said compound is 2-cyano-4-trifluoromethyl-6-nitro-N,N-di-npropylaniline.

8. Method as claimed in claim 2 wherein said compound is 2-cyano-4-trifluoromethyl-6-nitro-N-npropylaniline. 

1. HERBICIDAL COMPOSITIONS COMPRISING A HERBICIDALLY ACCEPTABLE CARRIER AND, AS AN ACTIVE COMPOUND AN EFFECTIVE AMOUNT OF A 6-NITROANILINE COMPOUND OF THE GENERAL FORMULA
 2. Methods of combating undesired vegetation which comprises applying an effective amount of a 6-nitroanile compound of the formula
 3. Method as claimed in claim 2 wherein said compound is applied to weeds growing in a crop to selectively damage the weeds without substantial injury to the crop.
 4. Method as claimed in claim 2 wherein R1 is hydrogen or alkyl of from 1 to 4 carbon atoms, and R2 is hydrogen, alkyl of from 1 to 4 carbon atoms or alkenyl of from 2 to 4 carbon atoms.
 5. Method as claimed in claim 2 wherein said compound is selected from the group consisting of 2-cyano-4-trifluoromethyl-6-nitro-N-n-butylaniline, 2-cyano-4-trifluoromethyl-6-nitro-N,N-di-n-propylaniline, 2-cyano-4-trifluorometHyl-6-nitro-N-n-propylaniline, 2-cyano-4-trifluoromethyl-6-nitroaniline, 2-cyano-4-trifluoromethyl-6-nitro-N-methylaniline, 2-cyano-4-trifluoromethyl-6-nitro-N-ethylaniline, 2-cyano-4-trifluoromethyl-6-nitro-N-2-hydroxyethylaniline, 2-cyano-4-trifluoromethyl-6nitro-N-2-methoxyethylaniline, 2-cyano-4-trifluoromethyl-6-nitro-N-isopropylaniline 2-cyano-4-trifluoromethyl-6-nitro-N-isobutylaniline.
 6. Method as claimed in claim 2 wherein said compound is 2-cyano-4-trifluoromethyl-6-nitro-N-n-butylaniline.
 7. Method as claimed in claim 2 wherein said compound is 2-cyano-4-trifluoromethyl-6-nitro-N,N-di-n-propylaniline.
 8. Method as claimed in claim 2 wherein said compound is 2-cyano-4-trifluoromethyl-6-nitro-N-n-propylaniline. 